The present invention relates to a recording unit used for fish sonars or the like and is provided with a recording needle which is simple in construction.
The conventional recording unit of this type has a support pivotally mounted on an arm made of a bent wire and a short recording needle is soldered to the support. A spring is mounted to the arm to urge this recording needle against a recording paper. One end of the spring is soldered to the arm and the other end is soldered to the support. A special adapter is required for securely fixing this arm to a belt, and a current collector similar to the recording unit is necessary to transmit recording signals to the recording needle, so that such a system is very complicated in structure and the manufacturing process is time-consuming.